Hot isostatic pressing apparatus and hot isostatic pressing methods for reducing surface-area chemical degradation on an article of manufacture

Abstract

A method for hot isostatic pressing includes the steps of providing or obtaining an article of manufacture, which optionally includes a copper or nickel alloy, disposing the article of manufacture in a shroud, the shroud defining an enclosed volume wherein the article of manufacture is disposed, the shroud being configured as a multi-piece joined structure to retard gaseous mass transport from outside the shroud to inside the enclosed volume, disposing the shroud in a containment vessel of a hot isostatic pressing apparatus and disposing a getter material in the shroud and / or in the containment vessel, and introducing an inert gas at an elevated temperature and pressure into the containment vessel for hot isostatic pressing.

Description

TECHNICAL FIELD[0001]The present disclosure generally relates to apparatus and methods employed in the manufacture of various articles. More particularly, the present disclosure relates to hot isostatic pressing apparatus and hot isostatic pressing methods for reducing surface-area chemical degradation on an article of manufacture.BACKGROUND[0002]Hot isostatic pressing, or “HIP,” is a method of manufacturing articles, which is used to reduce the porosity of metals and to increase the density of ceramic materials. The HIP process subjects the article to both an elevated temperature and an isostatic gas pressure in a high-pressure containment vessel. For pressurization, an inert gas is supplied, to reduce the any chemical reactions that may occur between the gas and the article. The vessel is heated, causing the pressure inside the vessel to increase. The heated, high-pressure gas is applied to the material from all directions, i.e., in an “isostatic” manner.[0003]While various effort...

AI Technical Summary

Problems solved by technology

While various efforts are made during the HIP process to exclude reactive gasses, such as oxygen, from the containment vessel, experience has shown that it is difficult to remove all reactive gas molecules from the vessel prior to the introduction of the inert gas.

Accordingly, though small, some amount (trace amounts, e.g., less than 10% by volume, or less than 5% by volume) of reactive gas remains in the containment vessel during the HIP process, which often results in some degree of contamination of the article.

Such oxides detrimentally affect the material properties of such articles, for example by altering the thermal conductivity thereof, and such oxides further interfere with subsequent manufacturing steps, such as plating, coating, and diffusion bonding.

It is thus apparent that the prior art remains deficient of suitable HIP apparatus and methods for inhibiting detrimental surface reactions, on a manufactured article undergoing HIP processing, caused by reactive gasses in the HIP containment vessel, without the need for close contact with scrap or packing materials and the like that could damage the article during HIP processing.

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